/**
 * flex布局
 */
 @mixin display-flex {
    display: -webkit-box;
    display: -webkit-flex;
    display: -moz-box;
    display: -ms-flexbox;
    display: flex;
}

@mixin flex($num) {
    -prefix-box-flex: $num;
    -webkit-box-flex: $num;
    -webkit-flex: $num;
    -moz-box-flex: $num;
    -ms-flex: $num;
    flex: $num;
}

@mixin flex-center {
    justify-content: center;
    align-items: center;
}